Common notice types
CP2000 (underreporter — IRS thinks income is missing). CP14 (balance due notice). CP501/CP503 (reminders for unpaid balance). CP504 (final notice before levy). LT11/Letter 1058 (final notice and intent to levy with right to a hearing). CP90 (intent to levy Social Security). Notice of Deficiency / 90-day letter (formal disagreement triggers 90-day window to petition Tax Court).
Read the notice carefully
Each notice states the issue, the amount, the deadline to respond, and the response options. Misreading the notice (or ignoring it) is the most common cause of escalation. Photocopy the notice and respond in writing on or before the deadline.
CP2000 specifics
A CP2000 proposes additional tax based on income shown on 1099s, W-2s, or other information returns that the IRS believes was missing from your return. You can agree (and pay), partially agree, or disagree (with explanation and supporting documentation). Most CP2000s settle through written response, often with no additional tax.
When to call vs write
Call only for clarification of the notice itself. Substantive responses go in writing — phone agents cannot make the binding decision and the call won't be in the record. Send responses by certified mail or by fax with confirmation, and keep copies of everything.
When to get representation
Anything beyond a routine CP2000, a 90-day letter (Notice of Deficiency), levy notices, or audit communications generally warrants engaging a CPA, EA, or tax attorney. The cost of representation is usually a fraction of the tax, penalty, and interest savings achieved through proper handling.
How experienced filers approach this
Experienced self-employed filers and the CPAs who advise them treat this question as a recurring planning exercise rather than a one-time decision. They model the multi-year tax impact rather than just the current year, document the reasoning in a short workpaper that survives staff turnover and software changes, and revisit the analysis annually as facts and laws change. The discipline is not difficult — a half-day in January with last year's return, the current-year IRS publications, and a spreadsheet — but it is rare among DIY filers, which is precisely why it produces outsized results.